The 67-year-old doctor-turned-activist had been receiving death threats for years since he began travelling by public buses to hundreds of villages around Maharashtra state to lecture against superstitions, religious extremism, black magic and animal or human sacrifice, according to his friend and fellow activist, Deepak Girme.

"He would say he was a medical doctor but that superstition was a bigger disease causing a lot of harm, especially to the poor and the gullible," Mr Girme said. "He wanted to expose the people who cheat the poor in the name of gods, who promise false cures for cancer or do black magic to perform so-called miracles."